An engine system, especially for a high horsepower engine, may include a turbocharger which includes a turbine and a compressor. Additionally, the engine system may include a waste gate assembly which diverts exhaust gases from the engine away from the turbocharger. Diverting exhaust gases away from the turbocharger may regulate the turbine speed and, therefore, regulate the speed of the compressor. In some engine systems, an internal waste gate assembly may be provided, however, alternative embodiments of engine systems include external waste gate assemblies.
The exhaust gases entering the waste gate assembly of an engine system are under high pressure. When the highly pressurized exhaust gases flow into the waste gate assembly, the gases come into contact with portions of a waste gate valve of the waste gate assembly. The high pressure differential across the waste gate valve may cause flow to accelerate beyond sonic levels which can result in the formation of a shock wave(s) within the waste gate assembly. Shock waves cause large pressure fluctuations which can lead to structural failures of portions of the waste gate assembly. Therefore, there is a need for a waste gate assembly which minimizes the likelihood of shock wave formation therein.